Path: ...!3.eu.feeder.erje.net!feeder.erje.net!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Bill Sloman Newsgroups: sci.electronics.design Subject: Re: The emitter-coupled monostable as slow differential amplifer Date: Sun, 21 Jul 2024 13:22:55 +1000 Organization: A noiseless patient Spider Lines: 50 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sun, 21 Jul 2024 05:23:13 +0200 (CEST) Injection-Info: dont-email.me; posting-host="27a374cf080d8d60bd047aa2610ca10b"; logging-data="4133800"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19GrXKNkYNnpsZQkgI7BwCd4CbTqUA0FfY=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:4Ch3iZbngX6tUdCffSR+DQsnlOs= X-Antivirus: Norton (VPS 240720-6, 20/7/2024), Outbound message In-Reply-To: X-Antivirus-Status: Clean Content-Language: en-US Bytes: 3190 On 21/07/2024 7:04 am, john larkin wrote: > On Sat, 20 Jul 2024 15:29:58 +1000, Bill Sloman > wrote: > >> About a month ago John Larkin dismissed the emitter coupled monostable >> with "It's really a slow diffamp, not a one-shot." >> >> If you feed a really slow pulse into it, it can look that way. >> The 3.3pf capacitor at C1 doesn't feed through much current if you drive >> the input with a slow edge >> >> The simulation below demonstrates it working exactly that way. >> >> No sensible circuit designer would deliberately drive it with a very >> slowly rising and falling pulse - if you want it to work as a >> monostable pulse stretcher, you have to drive it with a pulse that is >> narrower than the one you want to get out. >> >> Integrated circuit monostables don't have that limitation, but they are >> more complicated, and slower. There was an ECL monostable that went down >> to 10nsec, but the emitter-coupled monostable lets you get down to >> 1nsec, if you use it right. >> > > That wasn't my point. My comment wasn't about the trigger risetime but > that if you put in a long trigger, you get a long output. It's hardly > a one-shot. The input and output levels are weird too. The emitter-coupled monostable has been around for ages, and it's limitations have been well-known for just as long. > If course a proper one-shot should fire cleanly on a fast or slow > rising edge. Sadly, proper one-shots can't produce a 1nsec wide pulse. If you need that, you have to settle for a less-than-proper one-shot. Skilled circuit designers know about those kinds of compromises, and find work-arounds. John Larkin seems to confuse discussion and willy-waving. -- Bill Sloman, Sydney -- This email has been checked for viruses by Norton antivirus software. www.norton.com